With rapid development of mobile computing technology in recent times, mobile devices (for example, mobile phone, portable computer, personal digital assistant (PDA) and so on) may become a principle device for users to access and process digital information. In such a situation, it may become a trend to use mobile devices to access and process confidential data of enterprise or company or personal confidential information. For example, users, such as employees, may depend more and more upon a mobile working environment, such as mobile Outlook/Office client etc. Users may download confidential information, such as design documents or financial reports, to a personal mobile device for operation. However, such behavior may come with a potential risk of leaking information and introducing critical damage to an enterprise or the person itself.
Generally, a method for solving such problem may include encrypting data or setting access control permissions. However, security of data encryption relies on encryption strength, while encryption strength depends typically on the length of encryption, which may be further dependent on an encryption algorithm and mechanism used in the encryption process. Therefore, relatively large investments may be required to acquire an encryption method having superior performance as costs involved may be too high and implementation may be quite complicated. Besides, management of access control list may also results in a high cost and a complicated implementation due to its complex operating mode including maintenance of larger secure access control lists.